1. Field of the Invention
The present invention relates to a cutting insert with compound clearance faces for use in milling operations. The first clearance face proximal to the cutting edge is radiused and the second clearance face is planar.
The present invention further relates to cutting inserts which are pressed into final shape.
The present invention further relates to a cutting insert which achieves cutting face geometries and clearance faces which were formerly available only with ground type cutting tools.
The present invention further relates to a metal cutting insert having improved cutting edge strength.
2. Description of the Related Art
Kaminski, U.S. Pat. No. 5,071,291 discloses an internal disk milling cutter with an improved cutting insert. The cutting insert has a general wedge shape with an upper surface that is ground or otherwise formed .so as to be concave thereby creating a pair of coplanar cutting edges that sweep back symmetrically from a forward most cutting corner or point. In particular, the upper surface of the insert is comprised of a pair of flat, triangular top faces that slope downward at a shallow angle to the center of the insert. The pair of cutting edges thereby formed are generally V-shaped and coplanar.
There is no showing of the compound clearance faces present in the instant application. Accordingly, the present application differs from Kaminski '291.
Satran et al., U.S. Pat. No. 5,078,550 discloses a cutting insert for use in rotary milling cutters. The insert has a side relief flank and a side base edge defined between the side relief flank and a base surface. The side relief flank comprises a first and second component side relief flank surface which meet at an intersection line. The first component side relief flank extend along the side relief flank from a first position adjacent a leading end of the insert and located at an intermediate position thereof to a second position intersecting the cutting edge and adjacent a trailing end of the insert.
The component flank surfaces are substantially planar and are angularly disposed with respect to one another so that an insert side relief angle defined with respect to the cylindrical holder in the region of the leading end substantially equals an insert side relief angle in the region of the trailing end.
Satran '550 differs from the present invention because the component relief flank surfaces of Satran '550 are planar, whereas the component relief flank surfaces of the present invention are comprised of a convexly curved first relief flank surface, as seen in a side sectional view, and a planar secondary relief flank surface. It has been determined that a radiused primary clearance adjacent the cutting edge imparts improve strength to the cutting edge. Accordingly, the present invention differs from Satran '550.